Signal lantern and lens therefor



' I 2 May 1927 A. H. HANDLAN 6 7895 SIGNAL LANTERN AND LENS THEREFOR Filed Jan. 15, 1925 Patented May 10, 1927.

UNITEDISTATES PATENT OFFICE.

ALEXANDER H. HANDLAN, 01' 8'1. LOUIS, MISSOURI.

SIGNAL LANTERN AND LENS THEREFOR.

Application filed January ticularly in connection with signal lanterns of the types used on railroads and for controlling traific at street intersections where said signal lanterns were elevated above the heads of the persons Whose movements were controlled by said signal lanterns, due to the factthat it was practically impossible for an observer to see the signal given -b the signal lantern when he was immediate y beneath said signal lantern, or approximately in line with said signal lantern in a direction transverse to the direction of the beam of light cast thereby. The si nal lanterns in question were so arranged t at the lampv filament was concentrated as much as pos: sible in the principal focal point of the lens, which lens was usually of such character as to convert the light fallin thereon from the light sourceinto a beam w ich was projected toward the zone of observation. Such a beam, however, did not provide for close indication, that is, indication to one immediately beneath or above or to one or the other side of it, and at points close to the signal lantern. It frequently happened, therefore, that when a person had moved to a point beneath the signal lantern, or to a point where he was approximatel in line with it in a direction transverse to he direction of the beam of light cast thereby, he was unable to tell whether or not the desired signal was being flashed by the lantern.

The main purpose of my invention, therefore, is to produce a signal lantern which is provided with a lens so constructed and arranged that a signal given by said lantern may be observed even though the observer is out of the zone of-observation of the beam of light cast by said si nal lantern in a dianisms associated with these lanterns are 15, 1925. Serial No. 2,618.

usually located at the base of the standards by which said lanterns are supported, and heretofore itwas necessary for the maintenance man in testing the lanterns to manipu-' late the controlling mechanism and then walk some distance outwardly until he could see whether or not the signal was lighted. lVith my improved lens the maintenance man may remain at his position at the base of thestandard, as it is possible for him to see the signal from that point.

With the foregoing and other objects in view, the invention comprises the novel construction, combination and arrangement of parts hereinafter more specifically described and illustrated 'in the accompanying drawings, wherein is shown the preferred embodiment of the invention. However, it is to be understood that the invention comprehends changes, variations and modifications which come within the scope or the claims hereunto appended.

ig. I is a view, partly in side elevation and partly in vertical section, showing a Tignal lantern provided with my improved ens.

Fig. II is a perspective of the lens shown in Fig. I.

In the drawing, A designates a signal lantern of the type commonly used on railroads, said lantern comprising a housing B within which is located an incandescent lamp C. The lantern A is provided with a hood D which extends outwardly from the a lamp housing,.l:as shown in Fig. I.

1 designates'fthe lens of the lantern illustrated in Fig. I, said lens being provided with an annular flange 2 which is gripped by suitable fastening devices associated with the lantern housing whereby said lens is secured to said lantern housing. By referring to Figs. I and II it will be seen that the lens 1 is in the form of a hollow conoid and that said lens extends some distance outwardly from the adjacent marginal edge of the lantern housing. It will also be observed by referring to Fig-.111 that the lens 1 has prismatic zones 3 disposed on its inner face adjacent to the outermost end thereof, which zones are so formed and are in such positions relative to the source of light as to concentrate the light falling thereon from said light source into a beam which is projected toward the zone of observation.

Interposed between that portion of the inner face of the lens which is provided with by signal lanterns heretofore used and in addition to this a close-up signal is flashed which may be observed by a person who is immediaately beneath or above the signal lantern, or to one or the other side thereof. The flashing of these so-called close-up signals is rendered possible because the lens is in the form of a hollow conoid which is extended outwardly beyond the lantern housing, and because of the presence of the smooth skirt portion of the lens 1, for it is plain that when the incandescent lamp C is intensitied the interior of the hollow lens will be flooded with light, and this light will be radiated from said interior of said lens through the smooth annular skirt portion 4 thereof, whereby a subdued indication is provided which may be seen by one immediately beneath, above, or to one or the other side of the signal lantern, It is apparent, therefore, that the smooth skirt portion of the lens constitutes a very important feature of my invention, as it permits of a clear close-up signal being flashed which is not unduly dulled as it would be if the prismatic zones were disposed on the entire inner face of the lens.

An importantieature of my improved lens when used with railroad signal lanterns results from the fact that a very strong beam of light will be cast toward the zone of observation. where said beam may be picked 'up by the engineer of an approaching train, and because of the distance between the signal lantern and the engineer at this time he may look directly toward the lantern without being temporarily blinded by the intense light. As the engineer moves toward the signal lantern the intensity of the light, in so far as its effect on his eyes is concerned, is adually dimished, due to the fact that e is moving out of alinement with the beam of light. The gradual diminishing of the intensity of the light continues until the engineer is in line with the smooth skirt ortion 4 of the lens, when he may look irectly into the signal lantern without ill effects, due to the absence of prismatic zones on the skirt portion of the lens which would tend to intensify the light coming from the lantern. It is seen from this that a gradually subdued indication of the same color is obtained as the engineer moves from the point of greatest intensity of the light to a point relatively close to the signal lantern.

I claim:

1. A lens for traflic control signal lamps ing elements on a face of said conoid near the apex thereof, and a skirt portion designed for diffusing light extending rearwardly from said beam-forming elements to the rim portion of said lens.

2. A lens for traffic control signal lamps comprising a transparent member in the form of a hollow'conoid having beam-forming elements on a face of said conoid near the apex thereof, and a skirt portion designed for diffusing light extending rearwardly from said beam-forming elements to the rim portion of said lens, said skirt portion being of greater area than the portion occupied by the beam-forming elements.

In testimony that I claim the foregoing I hereunto aflix my signature.

ALEXANDER H. HANDLAN. 

